A thin, shiny red-brown or black layer, principally composed of iron manganese oxides, that coats the surfaces of many exposed desert rocks.
Black patina on the surface of rocks.
A gray or reddish-brown layer on rock surfaces that darkens and thickens with increasing age. Desert varnish results from microbial life processes that precipitate thin skins of clays and manganese oxide minerals. The thicknesses can be used to determine the amount of time the surface of a rock has been exposed. more details...
A glossy sheen or coating on gravel or stones in arid regions.
A dark, rusty-brown coating of iron oxide and magnesium oxide that accumulates on the surface of the rock.
A hard, dark, shiny coating on rocks caused by chemical action.
A dark coating commonly found on the surface of rock in the desert. It consists of clays, iron oxides, and magnesium oxides produced during weathering.
Desert varnish, or rock varnish is a dark coating found on exposed rock surfaces in arid environments. It is one of fourteen different types of rock coatings.